Pruritis Flashcards
Name some chemical mediators that can cause itching
Histamine, acetylcholine, interleukin 2
What type of nerve fibres transmit the itch sensation?
unmyelinated C fibres
What mediated the CNS response to itch?
Opiates (exogenous and endogenous)
Name stimuli that cause mast cell degranulation
Allergens, IgE binding, substance P, codeine
What pre formed mediators are released when a mast cell degranulates?
Proteases, Heparin, Histamine, Cytokines
What does the mast cell synthesise in response to mast cell degranulation?
Prostoglandins, leukotrienes, platelet activating factor
What is a pruritoreceptive itch?
something (usually associated with inflammation or dryness) in skin that triggers itch
What is a neuropathic itch?
damage of any sort to central or peripheral nerves causing itch
What is a neurogenic itch?
no evident damage in CNS, but itch caused by, e.g., opiate effects on CNS receptors
What is a psychogenic itch?
psychological causes with no (currently detectable) CNS damage, e.g. itch in delusions of infestation
What kind of itch do you get with stasis excema and why?
Pruritoceptive. There is direse exposure of the unmyelinated C fibres and this causes itching.
What kind of itch in associated with an insect bite?
Pruritoceptive
